As disclosed in U.S. Pat. No. 8,058,486, the compound 1,1,2,3-tetrachloro-propene (HCC-1230xa) is an important precursor that can be used for the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf), which is a low GWP molecule that can be used as an effective refrigerant, fire extinguishing agent, heat transfer medium, propellant, foaming agent, blowing agent, gaseous dielectric agent, sterilant carrier, polymerization medium, particulate removal fluid, carrier fluid, buffing abrasive agent, displacement drying agent and power cycle working fluid, to name but a few.
In normal practice, HCC-1230xa can be made in a two-step process using 1,1,3-trichloropropene (HCC-1240za or 1240za) and/or 3,3,3-trichloropropene (HCC-1240zf or 1240zf) as the starting material. In the first step, 1240za and/or 1240zf are chlorinated by Cl2 in one reactor to form the intermediate product 1,1,1,2,3-penta-chloropropane (HCC-240db or 240db) under certain reaction conditions:CCl2═CH—CH2Cl (1240za)+Cl2→CCl3—CHCl—CH2Cl (240db)CH2═CH—CCl3 (1240zf)+Cl2→CCl3—CHCl—CH2Cl (240db)
Next, the 240db is fed into another reactor and dehydrochlorinated by a catalyst (such as FeCl3) to form HCC-1230xa and HCl:CCl3—CHCl—CHCl (240db)→CCl2═CCl—CH2Cl (1230xa)+HCl
The present invention improves this two-reactor process by consolidating these two reactions into a single reactor, thus saving capital costs, simplifying the operation and improving both reaction times and product yield.